Origin Investigation of a Nitrogen-Related Recombination Center in GaAsN Grown by Chemical Beam Epitaxy

The origin of a N-related recombination center (E1), at around 0.33 eV below the conduction band minimum (CBM) of chemical beam epitaxy (CBE) grown GaAsN, is discussed based on effect of H implantation and dependence of E1 density to As flow rate (TDMAAs). After H implantation, E1 disappears completely whereas two new defects are recorded. The first one (HP1) is a hole trap at around 0.11 eV above the valence band minimum, similar to a N-related hole trap in unintentionally doped p-type GaAsN grown by CBE and expected to be N–H–V_Ga. The second level (EP1) is an electron trap at around 0.41 eV from CBM, identical to EL5 native defect in GaAs and expected to be V_Ga–As_i or As_Ga–V_Ga. The atomic structure of E1 is discussed from that of HP1 and EP1 and it is expected to be the split interstitial (N–As)_As. This expectation is supported by the peaking behavior of E1 density with As source flow rate.